For the first time, leaders from the advanced capitalist countries and those of the emerging economies seem to be on the same page when it comes to the urgency of slowing climate change.

From the vantage point of a few days out, the Paris climate summit looks set for success - at least by the metrics we've learned to use for these types of meetings. The main target for COP21, which is set to open on November 30, is to garner solid commitments aimed at reducing greenhouse gas emissions and setting a strict bar to keep global warming from passing the 2°C mark.

At first glance, this sounds a lot like the goals of previous climate meetings that ended up going nowhere. The 2009 Copenhagen meetingof 115 world leaders, for instance, was at first seen as a big opportunity to reverse climate change. Even before it ended though, the summit was widely panned as a failure. Most of its major goals for reducing CO2 emissions had to be dropped before a final communiqué could even be signed. But Paris could be different.

For the first time, leaders from the advanced capitalist countries and those of the emerging economies seem to be on the same page when it comes to the urgency of slowing climate change. Governments are declaring - in advance - their commitment to legally-binding targets and timelines for emissions reduction. That's a real advance compared to previous climate talks where there were only vague recognitions of climate change and pledges to do more. If governments stick to their commitments and follow through with real reductions, then Paris will be worth marking down as progress.

Reasons for optimism

So why are things shaping up so differently for COP21? A number of major political and economic developments portend a significant shift from what happened at Copenhagen.

After several years of wavering, President Obama forcefully rejected the Keystone XL pipeline in early November. By shutting down the plan to build a 1,700 mile pipeline to pump Canadian tar sands oil from Alberta down to Texas Gulf coast refineries, Obama helped set the stage for the discussions that will take place at COP21.

On the day of his decision, Obama declared, "If we're going to prevent large parts of this earth from becoming not only inhospitable but uninhabitable in our lifetimes, we're going to have to keep some fossil fuels in the ground." He continued, "America is now a global leader when it comes to taking serious action on climate change...approving that project would have undercut that global leadership, and that is the biggest risk we face: not acting."

Secretary of State John Kerry's comments at the time made it even clearer that the Administration had the upcoming Paris summit on its mind when making the decision. "The United States cannot ask other nations to make tough choices to address climate change if we are unwilling to make them ourselves," he said. "Denying the Keystone XL pipeline is one of those tough choices."

The symbolic importance of Keystone should not be underestimated. Stopping the pipeline was the biggest victory that the environmental movement has achieved in the U.S. in many years. It was proof that organized action could have an impact on policy debates.

But even more than that, it has sent the most powerful signal possible to other governments that America takes climate change seriously and is prepared to act. By pulling the plug on a pipeline that would have carried some of the world's dirtiest oil to market, Obama demonstrated that the U.S. is willing to be a serious partner in international efforts to tackle global warming. Presidential candidates Bernie Sanders and Hillary Clinton have both praised the President's decision.

Political developments in Canada have also contributed to a changed atmosphere for the Paris talks. The new prime minister, Justin Trudeau, was sworn in just days before Obama announced his decision. Though ostensibly a supporter of the Keystone pipeline, Trudeau was publicly against his predecessor Stephen Harper's aggressive lobbying on behalf of the TransCanada Corporation that planned to build it. Trudeau put up no real resistance to Obama's decision.

After Harper's loss, the changing of the guard in Canada has been swift. Trudeau moved the environment portfolio out of the Ministry of Natural Resources, which under Harper had prioritized tar sands exploration. Instead, he created a new Ministry of the Environment and Climate Change. The new foreign minister, Stephane Dion, previously led the Liberal Party on a "Green Shift" platform in 2008 and recently declared that climate change is the "worst threat we are facing this century."

The scuttling of Keystone has also gone a long way, especially among developing countries, to begin reversing the image of the U.S. as one who preaches but does not practice. It was preceded by the historic U.S.-China clean energy agreement last year, in which both countries agreed to move toward more renewables. The fact that the world's two biggest polluters have already hammered out an understanding before they arrive in Paris bodes well for a positive outcome.

China has long argued that the U.S. had its industrialization heyday and yet continues to produce more emissions per capita than any other nation. The new trend of cooperation between Obama and President Xi signals that the U.S. may be recognizing Chinese criticisms. Taking on the role of leader among developing economies, China has set a target of 20percent clean energy by 2030 and announced a few weeks back that it was implementing a national cap and trade carbon market beginning in 2017.

In Britain, meanwhile, the Conservative government of David Cameron has declared its intention to shut down its last coal-fired power plants by 2025. The country which pioneered the fossil-fueled Industrial Revolution of early capitalism is now on board with the changing international climate discussion.

The divisions in big oil

Where is the credit due for the major turnarounds on the climate issue by these leading governments? Recognition first of all goes out to the environmental and labor movements who have come together to push for stronger climate policies, as well as to the activists and governments of poor and developing countries who are already feeling the effects of climate change.

It is also necessary, however, to look at how divisions among the major energy companies are producing cracks in the coalition opposed to climate action. At a gathering of the world's top oil executives - the OPEC International Energy Seminar - in Vienna earlier this summer, major divisions over how to respond to COP21 and the growing commitment to environmental action were revealed.

While world oil prices are down over the last several months, no one believes that oil and coal will not continue to be major parts of the world's energy mix. This means that although the market outlook for producers of the dirtiest oil, like TransCanada, may be dimming, all the companies agreed that they will of course continue to invest heavily in their respective sectors. Where the façade of unity begins to break down, however, is on the issue of long-term prospects.

The major European oil companies - Royal Dutch Shell, BP, Total, Eni, BG Group, and Statoil - released a joint statement at the meeting calling for the development of a global carbon pricing system. The CEO of Shell, Ben van Beurden, told the meeting that the global energy system is experiencing "a transition from the traditional model based on oil and coal to a progressively cleaner, less carbon-intensive model." With an eye toward long-term profitability and market opportunity, these companies are already beginning to think about a post-fossil fuel future.

The head of Exxon Mobil, Rex Tillerson, took a completely opposite stance. In a strongly-worded warning to his fellow executives, Tillerson said that carbon pricing would destroy economic growth. He declared, "It is very important for governments that make those choices to live with the economic consequences." The imperatives of the short-term thinking inherent to the obsession with quarterly reports and shareholder returns seem to be motivating Exxon Mobil's perspective.

The model of a carbon pricing market being debated by these oil executives is a complicated one that has all kinds of shortcomings of its own, not least of which is its in-built inequalities for developing and developed economies. This is not the most important thing to take note of at the OPEC Executives conference though.

The most important thing to pay attention to is the fact that big oil is divided and this leaves an opening for progressives to pressure their governments. It has been said that powerful enemies can be vanquished, but only by the most "thorough, careful, attentive, skillful, and obligatory use" of any, even the smallest, of rifts among that enemy. These divisions among big oil are ones that need further attention and study.

Stumbling blocks remain

While there is reason to be optimistic about the Paris summit, it will not be smooth sailing.

The recent terrorist attacks in the French capital have greatly altered the terrain in which the talks will take place. The recent downing of a Russian military plane by Turkish forces further threatens to overshadow the environmental focus that governments had earlier put so much of their efforts into.

The heavy focus on security also means that the atmosphere surrounding the conference will probably be very different than anticipated. The dynamics of debate outside of the meeting hall look to be radically changed as French President Francois Hollande has banned demonstrations and public protests by environmental groups.

How this will affect the wide range of civil society parallel conferences and events that were planned to take place alongside COP21 is uncertain. It could mean that only the voices of governments and the most well-funded green groups will be heard. That is why it's all the more important to have progressive news coverage and analysis from on the ground in Paris.

Back here in the U.S., meanwhile, Republicans in the Senate are doing all they can to sabotage the Paris talks before they even begin. On November 24, they passed two resolutions aimed at blocking EPA regulations that would impose stricter emissions targets on power plants. The President will certainly veto the resolutions, but the main political goal is to undermine Obama at the Paris talks. The Republican plan is to make it look like Obama will be unable to carry through his pledges. West Virginia GOP Senator Shelly Moore Capito admitted as much when she said foreign diplomats "will take away a message from this vote...the general support for the direction he's going is weak at best."

Many of the major oil companies, like Exxon Mobil and TransCanada, will also certainly be on the job the morning after the summit concludes to try to water down and derail any commitments that threaten their profits and investment plans. Lobbyists in Washington, Ottawa, and many other capitals will be hard at work to put a check on the drive to halt climate change.

COP21 has the potential to be big. Just like the lobbyists of big oil will be doing though, progressive activists and the climate justice movement will have to roll up their sleeves and get down to work if they want to make the pledges of Paris a reality.